One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(9,10,12,14)(11,13,15,16)(17,18)(19,21)(20,22)(23,24)(27,33)(28,35)(30,37)(32,38)(34,39)(36,40)(2,5)(6,8)(9,11)(10,13)(12,15)(14,16)(17,19,20,23)(18,21,22,24)(25,26)(27,34)(28,32)(29,31)(30,36)(33,39)(35,38)(37,40)(2,5)(3,7)(11,15)(13,16)(25,27,35,40,29,36,28,33)(26,30,38,39,31,34,32,37)(1,3,4,7)(2,6,5,8)(18,22)(21,24)(26,31)(30,34)(32,38)(37,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.